Perhaps you should try some spelling variations:
dieu hien » dieu khien, dieu kien, bieu hien
vat thanh » dat thanh, gat thanh, tat thanh
thanh dai » thanh hai, thanh tai, thanh dat
sach thu » sach thue, sach thieu, sach tham
dai thuc » dan thuc, dai thu, dai thua
sach tu » cach tu, sach ty, sach uu
va hoa » van hoa, ma hoa
va hoc » van hoc

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach tu) OR (sach thu)) hang ((va hoa) OR (va hoc)). dieu hien dai thuc vat thanh dai cua vat~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach tu) or (sach thu)) hang ((va hoa) OR (va hoc)). dieu hien dai thuc vat thanh dai cua vat~".
• Adding a wildcard symbol may retrieve word variants: su ((sach tu) or (sach thu)) hang ((va hoa) OR (va hoc)). dieu hien dai thuc vat thanh dai cua vat*.